I put my kids in Tae-kwon-do. The instructor taught them for me.
There's a fine line between the need to defuse a situation and defending yourself. I think we would all naturally try to defuse first, but if the need arises, they need to know how to:
1.) not get hurt, (defense)
and
2.) stop someone from hurting them (offense)
Tae-kwon-do is generally known as a defensive-type martial arts technique, which employs avoidance manuevers, but they know how to stop someone from hurting them too. At the center of it all is self-control, to make good judgements when confronted.